Let's think!

• In nature, ¾ of the volume of the Earth's surface is occupied by H 2 O, and CO 2 is an obligatory component of the atmosphere. What is the classification of oxide? What does it form with H 2 O.
• Compose the equations for the reactions of the interaction of carbon dioxide with water and characterize this reaction.

CO 2 + H 2 O↔H 2 CO 3

Carbonic acid and its salts

Lesson topic

Carbonic acid

• Chemical formula - H 2 CO 3
• Structural formula - all bonds are polar covalent

• The acid is weak, exists only in an aqueous solution, is very fragile, decomposes into carbon dioxide and water:
• H 2 CO 3 ↔CO 2 + H 2 O
• In ionic equations we write
• H 2 CO 3 ↔ H 2 O+CO 2

coal

Medium salts -

Acid salts -

carbonates

bicarbonates

Salts of carbonic acid, their solubility

Chemical formula

Name

Solubility

soda ash

drinking soda

Chalk, marble, limestone

The value of salts of carbonic acid

calcined

crystalline

Na 2 CO 3 10 H 2 O

Production

Production

Production

soap, at home

like detergent

means.

The use of salts of carbonic acid

Chemical formula of a substance

Trivial (historical) name

ZnCO 3

Modern name

Galmey

Na 2 CO 3

Substance use

NaHCO 3

Zinc carbonate

soda ash

drinking soda

Paint production.

Na 2 CO 3 10H 2 O

Sodium carbonate

MgCO 3

crystal soda

Water softening, glass production.

sodium bicarbonate

In the food industry, in medicine.

Sodium carbonate decahydrate

MgCO mixture 3 and CaCO 3 (1:1)

Burnt magnesia

(CuOH) 2 CO 3

Dolomite

For softening water when washing clothes.

magnesium carbonate

In medicine.

Mixture of magnesium and calcium carbonates

Malachite

K 2 CO 3

In construction.

Basic copper(II) carbonate

Potash

CaCO 3

crafts, Jewelry.

Potassium carbonate

Chalk, marble, limestone

Production of glass, ceramics, cement, fertilizer.

Calcium carbonate

Production of building materials.

Carbonates in sculpture and architecture

Parthenon (5th century BC Athens)

Nike of Samothrace

(11th century BC Louvre. Paris)

Chemical properties of carbonates and hydrocarbonates

1) Qualitative reaction to CO 3 2- carbonate - ion "boiling" under the action of a strong acid :

CaCO 3 + 2HCl \u003d CaCl 2 + H 2 O + CO 2

NaНCO 3 + HCl \u003d NaCl + H 2 O + CO 2

2) Enter into exchange reactions with other soluble salts

Na 2 CO 3 + CaCl 2 \u003d CaCO 3 ↓ + 2NaCl

3) Decomposition of bicarbonates and carbonates when heated

NaHCO3 t˚C → Na 2 CO 3 + H 2 O + CO 2

CaCO3 t˚C → CaO + CO 2 (excluding metal carbonates I A gr.)

4) Carbonates and bicarbonates can turn into each other

CaCO 3 + CO 2 + H 2 O \u003d Ca (HCO 3) 2

• Hydrocarbons cause temporary hardness of water

Ways to eliminate temporary water hardness

1. Boiling

When boiled, soluble calcium and magnesium bicarbonates are converted into insoluble carbonates.

2. Addition of soda (Na 2 CO 3 )

Eliminates not only temporary, but also permanent water hardness created by chlorides and sulfates of calcium and magnesium.

Exercise:

Write the molecular equations for the corresponding reactions.

Set the correspondence between the left and right sides of the equations

right parts

equations

a) K 2 SO 4 + 2CO 2 + 2H 2 O

c) K 2 CO 3 + CO 2 + H 2 O

e) 2NaCI + CO 2 + H 2 O

f) K 2 SO 4 + 2H 2 O

left hand sides of equations

the heating

the heating

3) Na 2 CO 3 + 2HCI =

4) CaCO 3 + CO 2 + H 2 O \u003d

5) 2KHCO 3 + H 2 SO 4 =

Let's check

"5" - no errors;

"4" - 1 error;

"3" - 2 errors;

"2" - 3 errors

Here, among the millions of crystals of calcite and aragonite, it is difficult for a person to understand

what forces of nature could create this stone miracle.

Rainwater, seeping through the roof of a limestone cave, dissolves the limestone contained in the rock. Of course, the water does not flow down from the arch of the cave in a stream, but drips very slowly, so slowly that part of it has time to evaporate, and the limestone dissolved in it again crystallizes in the form of stone “icicles” hanging from the ceiling. This is how stalactites are formed. Drops of lime water that have fallen down also evaporate, and the limestone dissolved in them remains at the place where the drops fall, forming vertical cone-shaped growths - stalagmites.

mutual transformations in nature Cave "Emine-Bair-Khosar" in the Crimea!

Test on the topic carbonic acid

1. What is the characteristic not applicable to coal

acid:

1) unstable 2) dibasic 3) strong

2. Drinking Soda Formula:

1) NaHCO 3 2) Ca(HCO 3 ) 2 3) Na 2 SO 3

3. Substance with which carbonates are recognized:

1) Ca(OH) 2 2) HCl 3) BaCl 2

4. Condition necessary for the decomposition of carbonates:

1) temperature

2) pressure

3) light

5. Where is baking soda used?

1) in the confectionery business

2) in construction

3) in glass production

Let's check

Grades: "5" - no errors;

"4" - 1 error;

"3" - 2 errors

Homework

• Study the paragraph in the textbook.
• Make up the reaction equations according to the scheme:
• 1) Ca → CaC 2 → Ca(OH) 2 → CaCO 3 → CO 2 →C
• 2) CO 2 → H 2 CO 3 → Na 2 CO 3 → CO 2

• To solve the task.

What volume and mass of carbon dioxide will be released during the firing of calcium carbonate weighing 400 g.

Bozadzhi N.M.

chemistry teacher

Tell me and I will forget

Show me and I will remember

Involve me and I will learn!

Chinese wisdom

Target: After reading the fragment, choose the correct answer by writing the letter of the correct answer and as a result - the topic of our lesson!

1. Coal is the most valuable of the minerals, - the engineer replied, - and nature seems to have decided to prove this by creating a diamond, because it is, in essence, nothing more than crystalline carbon.

J. Verne "Mysterious Island"

K) graphite

A) carbine

P) fullerene

2 .Meanwhile, the Needlewoman returns, strains the water, pours it into jugs, and what an entertainer: if the water is unclean, she will fold a sheet of paper, put coals in it and pour coarse sand, insert that paper into a jug and pour water into it, and water - then, you know, it passes through the sand and through the coals and drips clean, like crystal, into a jug.

Russian folk tale"Moroz Ivanovich"

B) filtration

BUT) distillation

O) adsorption

M) crystallization

3. Carbon monoxide! cried Holmes. “Wait a little. Now he will leave.

Looking through the door, we saw that the room was lit only by a dim blue flame, flickering in a small copper brazier in the middle ... A terrible poisonous fumes were drawn into the open door, from which we choked and coughed.

A.K. Doyle "The Case of the Translator"

3. Find the chemical errors in the read passage. Why couldn't Holmes and his companions determine the presence of carbon monoxide in the room by the signs described?

H) carbon monoxide is odorless

G) carbon monoxide has a pleasant smell

BUT) When you have carbon monoxide poisoning, you don't cough

4. A tree grows in the Arabian desert caratina silikva (caratina siliqua), the fruit stones of which always have the same weight in any year and on any tree. Therefore, the jewelers of antiquity used such weights for their scales, calling them carats. Nowadays, there is a carat test of gold and precious stones.

AND) 100 g

H) 0.5 g

T) 0.2 g

R) 0.1 g

5 . - Have you heard about the "dog cave" effect in Italy? There is a cave there. The person will enter and walk around, and the dog or rabbit will die in a few minutes.

- Why?

- Carbon dioxide is released from a volcanic fissure...

V. Korotkevich "Black Castle Olshansky"

S) SO 2 heavier than air and accumulates at the bottom

BUT) SO 2 safe for humans but harmful to animals

AND) a man enters a cave wearing a gas mask

5. Why does a person remain alive in the “dog cave”, while dogs and other small animals die?

• Questions

1 2 3 4 5

K A R B O N A T Y

• What carbonates ? cabonates - these are salts of carbonic acid, which will be the subject of discussion in today's lesson.

As a result of studying the topic, you will be able to:

• giving characterization of coal
• giving characterization of coal

acid and its properties .

2. Simulate

3. Consider

4. Simulate

5. Write reaction equations

6.Exercise reflection of their activities

• acid and its properties . 2. Simulate methods for producing carbonic acid 3. Consider properties of salts of carbonic acid. 4. Simulate qualitative reaction to the carbonate ion 5. Write reaction equations 6.Exercise reflection of their activities

• Carbonic acid - weak dibasic acid with chemical formula H 2 CO 3

Exercise 1. Write reaction equations

stepwise dissociation of carbonic acid:

H 2 CO 3 H + + HCO 3 -

HCO 3 - H + + CO 3 2 -

H 2 CO 3 2H + + CO 3 2 -

NB! dibasic, forms 2 types of salts:

medium - carbonates (ions CO 3 2- )

acidic - hydrocarbons (HCO ions 3 - )

• Carbonic acid is unstable, not isolated in its pure form, as it easily decomposes into carbon dioxide and water (the process is reversible)

H 2 CO 3 CO 2 +H 2 O

An experience

1. Dissolving carbon dioxide in water

CO2 + H2O H2CO3

2. Interaction of salts (carbonates and bicarbonates) with stronger acids .

NaHCO 3 +HCI=

Na 2 CO 3 +2HCI=

IV. Salts of carbonic acid and their solubility

Chemical formula

Name

Solubility

soda ash

drinking soda

Chalk, marble, limestone

1) Interaction of bicarbonates with acids

Na H CO 3 + HCl =

drinking

soda

2) Enter into exchange reactions with other soluble salts

Na 2 CO 3 + CaCl 2 =

NaCl + H 2 O + CO 2

CaCO 3 ↓ + 2 NaCl

Chemical properties of carbonates and hydrocarbonates

3) Carbonates and bicarbonates can turn into each other

CaCO 3 + CO 2 + H 2 O \u003d Ca (HCO 3 ) 2

Ca(HCO 3 ) 2 = CaCO 3 + CO 2 + H 2 O

4) Decomposition of bicarbonates and carbonates when heated

NaHCO 3 t˚C → Na 2 CO 3 + H 2 O+CO 2

CaCO 3 t ˚ C → CaO + CO 2

Exception:

metal carbonates I groups, ch. subgroups

Chemical properties of carbonates and hydrocarbonates

Hydrocarbons cause temporary hardness of water.

Ways to eliminate temporary hardness of water:

1. Boiling

When boiled, soluble calcium and magnesium bicarbonates are converted into insoluble carbonates.

2. Adding soda ( Na 2 CO 3 )

Eliminates not only temporary, but also permanent hardness of water created by chlorides and sulfates of calcium and magnesium.

VI. Determination of carbonates

Determination of carbonate - ions

CaCO 3 + 2HCI \u003d CaCI 2 + H 2 CO 3

CO 2 + Ca(OH) 2 \u003d CaCO 3 ↓ + H 2 O

VII. Importance of carbonates

• Among carbonates, calcium carbonate deserves special attention. CaCO3 , met as:

limestone marble chalk

VII. Importance of carbonates

Three brothers live on earth

From the carbonate family.

Elder brother - handsome - Marble,

Glorious in the name of Karara,

Excellent architect. He

He built Rome and the Parthenon.

Everyone knows Limestone,

That's why it's named like that.

Famous for his work

Building a house behind the house.

VII. Importance of carbonates

And able and able

The younger soft brother Mel.

How to draw, look

This CaCO 3 .

Brothers love to frolic

Burn in a hot oven.

CaO and CO 2 are formed then.

It's carbon dioxide

Each of you is familiar with him,

We breathe it out.

VII. Importance of carbonates

Well, this is CaO -

hot burnt

LIME FAST.

Add water to it

mixing carefully,

To avoid trouble

protect hands.

Cool mixed LIME,

but DONE!

milk of lime

magnified.

VII. Importance of carbonates

The bright house cheered up

Turning lime into chalk.

Hocus pocus for the people:

All you have to do is blow through the water

How easily it turns into milk!

And now I'm getting a soda rather deftly:

Milk plus vinegar, Ay!

Foam pours over the edge!

All in worries, all in work

From dawn to dawn -

These brothers the Carbonates,

Chemical formula of a substance

Trivial (historical) name

Modern name

Application

substances

Zinc carbonate

soda ash

drinking soda

Paint production.

Na 2 CO 3 10H 2 O

Sodium carbonate

crystal soda

Water softening, glass production.

sodium bicarbonate

In the food industry, in medicine.

Sodium carbonate decahydrate

Mixture of MgCO 3 and CaCO 3 (1:1)

Burnt magnesia

For softening water when washing clothes.

magnesium carbonate

In medicine.

Mixture of magnesium and calcium carbonates

In construction.

Basic copper(II) carbonate

Crafts, jewelry.

Potassium carbonate

Chalk, marble, limestone

Production of glass, ceramics, cement, fertilizer.

Calcium carbonate

Production of building materials.

Reflection

Exercise 1. Write the reaction equation for the preparation of calcium carbonate from calcium hydroxide

Ca(OH) 2 +CO 2 = CaCO 3 + H 2 O

Task 2. How to get calcium bicarbonate from calcium carbonate? Write the reaction equation.

CaCO 3 ↓ +H 2 O+CO 2 = Ca(HCO 3 ) 2

Exercise 3 . Is the reverse transformation possible? If so, what are the methods of transformation.

t 0

Ca(HCO 3 ) 2 = CaCO 3 + H 2 O+CO 2

Ca(HCO 3 ) 2 + Na 2 CO 3 =CaCO 3 +2NaHCO 3

Exercise 4 . Set the correspondence between the left and right sides of the equations

right parts

equations

a) K 2 SO 4 + 2CO 2 + 2H 2 O

b) Ca(HC O 3 ) 2

in) K 2 CO 3 + CO 2 + H 2 O

G) CaO+CO 2

e) 2NaCl + CO 2 + H 2 O

left hand sides of equations

t o

1 ) 2KHCO 3 →

t o

2)CaCO 3 →

3) Na 2 CO 3 + 2HCI →

4) FROM aCO 3 +CO 2 +H 2 O →

5)2KHCO 3 + H 2 SO 4 →

Answer: 1 - in; 2 -d; 3d; 4-b; 5-a

1. At the lesson I worked ... 2. With my work in the lesson, I ... 3. The lesson seemed to me ... 4. For the lesson I ... 5. My mood… 6. The material of the lesson was ...

active, satisfied, short, not tired, useful, better, understandable, interesting, easy.

• Read and study the abstract.
• Repeat paragraph: § 4.14.2
• Complete tasks:

work in groups exercise 1 (9-15) p.112

To use the preview of presentations, create an account for yourself ( account) Google and sign in: https://accounts.google.com

Slides captions:

Do you know that…..? On April 24, 1833, carbonated soda water was patented in the United States. The first carbonated drink was obtained in 1767 by the brilliant English chemist Joseph Priestley. He discovered one of the properties of carbon dioxide, with the help of which the production of carbonated water became possible.

The composition of sparkling water Bottled sparkling water is enriched with CO 2 , which purifies water from microbes. Carbon dioxide also increases the shelf life of water and acts as a preservative. The presence of carbon dioxide in a drink or water as a preservative is marked on the label with the code E290. When carbon dioxide combines with water, carbonic acid is formed.

Carbonic acid and its salts

Carbonic acid Chemical formula - H 2 CO 3 Structural formula - all polar covalent bonds The acid is weak, exists only in aqueous solution, very fragile, decomposes into carbon dioxide and water: CO 2 + H 2 O ↔ H 2 CO 3 We write in ionic equations H 2 CO 3 ↔ H 2 O + CO 2

Carbonic acid Dibasic, forms salts: - medium - carbonates (ions CO 3 2-) - acidic - hydrocarbonates (ions H CO 3 -)

Salts of carbonic acid are crystalline solids. most of them do not dissolve in water. Dissociation: with the formation of carbonate anions, hydrocarbonates are solid crystalline substances. dissolve in water Dissociation: with the formation of a hydrogen cation, a carbonate anion.

Chemical properties of carbonates and hydrocarbonates 1) Qualitative reaction to CO 3 2-carbonate - ion "boiling" under the action of a strong acid: Chalk Ca CO 3 + 2HCl \u003d C aCl 2 + H 2 O + CO 2 Baking soda Na H CO3 + HCl \u003d NaCl + H 2 O + CO 2 2) Enter into exchange reactions with other soluble salts Na 2 CO 3 + CaCl 2 = CaCO 3 ↓ + 2 NaCl 3) Carbonates and bicarbonates can turn into each other Ca (OH) 2 + CO 2 \u003d CaCO 3 ↓ + H 2 O CaCO 3 + CO 2 + H 2 O \u003d Ca (HCO 3) 2 4) Decomposition of bicarbonates and carbonates when heated NaHCO 3 t˚C → Na 2 CO 3 + H 2 O + CO 2 CaCO 3 t ˚ C → CaO + CO 2

for carbonates, bicarbonates CaCO 3 NaHCO 3 Qualitative reactions To check the presence of carbonates, you need to add any acid CaCO3 + 2H+ ↔ Ca2+ + H2O + CO2 chalk Baking soda

The Red Cave, or Kizil-Koba, is the largest of 800 Crimean caves. It is located 3.5 km from the village of Perevalnoye in the picturesque Kizil-Koba tract, which is a natural monument and is protected by the state. The total length of the studied part of the cave is 14 km. The part that has not been passed between the Proval cave and the Fifth landslide hall is about 3.5 km more. Kizil-Koba is a complex, intricate labyrinth, located on six floors with an amplitude of 135 m. The oldest sixth floor is about two million years old.

stalagmites

Stalactite "Pot-bellied"

Stalactite "Fire"

Cave "Emine-Bair-Khosar" in Crimea

Stalactites and stalagmites in the cave of Avshalom, Israel

Application of salts of carbonic acid Chemical formula of the substance Trivial (historical) name Modern name Application of the substance ZnCO 3 Galmei Zinc carbonate Production of paints. Na 2 CO 3 Soda ash Sodium carbonate Water softening, glass production. NaHCO 3 Baking soda Sodium bicarbonate In the food industry, in medicine. Na 2 CO 3 ·10H 2 O Soda crystalline Sodium carbonate decahydrate For softening water when washing clothes. MgCO 3 Burnt magnesia Magnesium carbonate In medicine. Mixture of MgCO 3 and CaCO 3 (1:1) Dolomite Mixture of magnesium and calcium carbonates In construction. (CuOH) 2 CO 3 Malachite Basic copper (II) carbonate Crafts, jewelry. K 2 CO 3 Potash Potassium carbonate Production of glass, ceramics, cement, fertilizer. CaCO 3 Chalk, marble, limestone Calcium carbonate Manufacture of building materials.

Prepared by a chemistry teacher MOU secondary school No. 1, r.p. Novospasskoe Ninasheva R.T. chemistry lesson in grade 9 Carbonic acid and its salts Let's think!

• In nature, ¾ of the volume of the Earth's surface is occupied by H2O, and CO2 is an obligatory component of the atmosphere. What is the classification of oxide? What does it form with H2O.
• Write the reaction equations for the interaction of carbon dioxide with water and give physical and chemical characteristics this reaction.

• Which?
• For what?
• How will we study?

• Chemical formula- H2CO3
• Structural formula- all bonds are polar covalent
• The acid is weak, exists only in an aqueous solution, is very fragile, decomposes into carbon dioxide and water:
• CO2 + H2O ↔ H2CO3
• In ionic equations we write
• H2CO3 ↔ H2O + CO2

• Dibasic, forms salts:
• - medium - carbonates (ions CO32-)
• - acidic - bicarbonates (ions HCO3-)

• 1) Qualitative reaction to CO32-carbonate - ion "boiling" under the action of a strong acid :
• Chalk CaCO3 + 2HCl = CaCl2 + H2O + CO2-
Drinking soda NaНCO3 + HCl = NaCl + H2O + CO2 2) Enter into exchange reactions with other soluble salts
• Na2CO3 + CaCl2 = CaCO3↓ + 2NaCl
3) Carbonates and bicarbonates can turn into each other
• Ca(OH)2 + CO2 = CaCO3↓ + H2O
• CaCO3 + CO2 + H2O = Ca(HCO3)2
• 4) Decomposition of bicarbonates and carbonates when heated
• NaHCO3 t˚C → Na2CO3 + H2O + CO2
• CaCO3 t˚C → CaO+CO2

Here, among the millions of crystals of calcite and aragonite, it is difficult for a person to understand

what forces of nature could create this stone miracle.

Cave "Emine-Bair-Khosar" in Crimea Stalactites and stalagmites in the cave Avshalom, Israel Stalactites and stalagmites in the cave Avshalom, Israel The use of carbonic acid salts

• No. 1. Level A.
• Complete the equations of feasible chemical reactions:
• CO 2+ NaOH =
• With O2+ Na2O =
• CO2 + Ca(OH)2 =
• H2CO3+ Na2SO4 =
• CaCO3 + CO2 + H2O =
• No. 2. Level B.
• Make up the reaction equations according to the scheme:
• 2) Ca → CaC 2 → Ca (OH) 2 → CaCO 3 → CO 2 → C
• 3) CO2 → H2CO3 → Na2CO3 → CO2

• j) carbon monoxide (IV)
• l) carbon monoxide (II)
• l) nitric oxide (V)
7. Compare carbon dioxide to air
• c) lighter than air
• m) heavier than air
• y) the same
8. Strong poison, replaces oxygen in blood hemoglobin
• h) carbon monoxide (IV)
• i) carbon monoxide (II)
• j) nitric oxide (V)
9. When extinguishing fires use
• c) carbon monoxide (II)
• m) carbon monoxide (IV)
• y) nitric oxide (V)

• Study the paragraph in the textbook. To solve the task.
• What volume and mass of carbon dioxide will be released during the firing of calcium carbonate weighing 400 g.

Carbonic acid and its salts

STRUCTURE AND PROCESS OF THE LESSON

Target : the acquisition of knowledge about the properties of carbonic acid and its salts and their application.

Tasks .

Educational.

1. To study the general and specific properties of carbonic acid and its salts.
2. To reveal the features of carbonic acid and its salts and their applications.
3. Continue the formation of skills in compiling reaction equations.

Educational.

Create conditions for:

1. Increasing the cognitive activity of students;
2. Development of the ability to work in a team;
3. Education of a common culture;
4. upbringing responsibility and accuracy, communication skills, respect for comrades;
5. upbringing positive attitude towards chemistry;

Developing.

Create conditions for the development of UUD:

1) Cognitive:

• General educational universal actions:

1. Conscious and arbitrary construction of speech utterance.
2. Semantic reading, definition of primary and secondary information.
3. Choosing the most effective ways to solve problems.
4. Reflexive UUDs.
5. Structuring knowledge.

• Sign-symbolic actions:

1. Writing reaction equations (sign-symbolic).

• Boolean Generic Actions:

1. Analysis of objects in order to extract features.
2. Establishment of causal relationships.
3. The ability to analyze, build a research plan, observe and draw conclusions based on the experiment, make deductive and inductive conclusions.
4. Using experience as a source of knowledge; the ability to conduct and describe an experiment, observe and draw conclusions in chemical language.
5. Proposing hypotheses, their justification.

• Statement and solution of the problem.

2) Personal: independent creation of ways to solve search problems.

3) Communicative:

1. asking questions,
2. The ability to accurately express one's thoughts
3. Possession of dialogical speech,
4. Collaboration in a group.

4) Regulatory:

1. Goal setting.
2. Planning.
3. Control in the form of comparing the result of an action with a given standard in order to detect deviations and differences from the standard.
4. Grade.
5. Self-regulation.

Lesson type: A lesson in learning new material.

Criteria for achieving the goal of the lesson: student must

KNOW:

1) Chemical properties of carbonic acid and its salts.

2) Qualitative reaction to the carbonate ion.

3) Natural compounds of carbonic acid.

4) Names of salts of carbonic acid and their practical application.

BE ABLE TO:

1) Describe carbonic acid and its salts.

2) Write down the formulas of acid and medium salts and name them.

3) Write down the reaction equations confirming the main Chemical properties salts in molecular and ionic form.

4) Practically determine the presence of CO anions 3 2- and HCO 3 - in solution.

5) Explain the interconversions of carbonates and bicarbonates in nature.

Teaching methods:active learning methods: heuristic conversation, group work - laboratory work in a research setting.

During the classes

I. Organization of students for work.

Greetings: I'm glad to meet you. Today we will continue our study of carbon compounds. Before the start of the lesson, I wish you Have a good mood and creative success, I hope that our meeting will be fruitful.

Frontal work with the class on the literary-chemical test.

1. Coal is the most valuable of minerals, the engineer replied, and nature seems to have decided to prove this by creating a diamond, because it is, in essence, nothing more than crystalline carbon. J. Verne "Mysterious Island"

What allotropic modifications of carbon, besides diamond, do you know?

B) ozone

K) graphite

A) carbine

P) fullerene

2 .Meanwhile, the Needlewoman returns, strains the water, pours it into jugs, and what an entertainer: if the water is unclean, she will fold a sheet of paper, put coals in it and pour coarse sand, insert that paper into a jug and pour water into it, and water - then, you know, it passes through the sand and through the coals and drips into a jug clean, like crystal.

Russian folk tale "Moroz Ivanovich"

What cleaning methods does Needlewoman use?

B) filtering

A) distillation

O) adsorption

M) crystallization

3. Carbon monoxide! Holmes exclaimed. Wait a bit. Now he will leave. Looking through the door, we saw that the room was lit only by a dim blue flame, flickering in a small copper brazier in the middle ... A terrible poisonous fumes were drawn into the open door, from which we choked and coughed.

A.K. Doyle "The Case of the Translator"

Find the chemical errors in the passage you read. Why couldn't Holmes and his companions determine the presence of carbon monoxide in the room by the signs described?

H) carbon monoxide is odorless

D) carbon monoxide has a pleasant smell

A) when carbon monoxide poisoning, a person does not cough

4. In the Arabian desert grows the tree Caratina silikva (Caratina silikva), the fruit seeds of which always have the same weight in any year and on any tree. Therefore, the jewelers of antiquity used such weights for their scales, calling them carats. Nowadays, there is a carat test of gold and precious stones.

What is the weight of one carat?

I) 100 g

H) 0.5 g

T) 0.2 g

P) 0.1 g

5 . - Have you heard about the “dog cave” effect in Italy? .... There is such a cave-pit there. The person will enter and walk around, and the dog or rabbit will die in a few minutes.

Why?

Carbon dioxide is released from a volcanic fissure...

V. Korotkevich "Black Castle Olshansky"

Why does a person remain alive in a “dog cave”, while dogs and other small animals die?

S) CO 2 heavier than air and accumulates at the bottom

A) CO 2 safe for humans but harmful to animals

G) a man enters a cave wearing a gas mask.

III. Transition to the study of new material: (3 min)

What word is formed from the letters corresponding to the correct answers?

What are carbonates? So, the topic of today's lesson is "Carbonic acid and its salts." (Setting goals and objectives of the lesson)

What do you need to know about these substances? (Chemical formulas, physical and chemical properties, application). These will be the objectives of our lesson.

IV. Learning new material.

Teacher : Opening a bottle of lemonade, Pepsi-Cola or any other carbonated drink, we are faced with our stranger. It's carbonic acid. How often it treacherously breaks out of the bottle, splashing around. This is due to the fact that its molecules are extremely unstable, and in the bottle it is under great pressure, when we open the lid, it immediately decomposes:

H 2 CO 3 \u003d H 2 O + CO 2

Carbonic acid is that rare case of a substance whose formula is considered to be conditional, that is, such a molecule does not exist, but it is possible to consider not only the properties of its compounds, but also the intrinsic properties of this acid.

R.t. With. 184 No. 1 - let's characterize this acid.

According to the degree of dissociation, carbonic acid is weak, dissociates in two steps and forms two series of salts

R.t. With. 184 No. 2, using the solubility table, give examples of salts.

Propose a plan for studying the chemical properties of carbonates. (interaction with acids, salts, special properties of carbonates)

Let's perform lab experiments in groups

1. The interaction of carbonates with acids
2. Interaction of carbonates with salts
3. Special properties of carbonates

1. All salts interact with acids - they give a qualitative reaction to CO ions 3 2- and HCO 3 -

MeCO 3 + H n KO → MeKO + CO 2 + H 2 O

MeHCO 3 + H n KO → MeKO + CO 2 + H 2 O

Laboratory experiment "Interaction of marble and sodium carbonate solution with a solution of hydrochloric acid» - notebook for lab experiments

2) Solutions of salts of carbonic acid interact with solutions of other salts if insoluble substances are formed.

(Demonstration "Interaction of sodium carbonate solution with calcium chloride solution")

1. Special properties of carbonic acid:

A) salts of carbonic acid decompose when heated

MeCO 3 → MeO + CO 2 (excluding alkali metal carbonates)

MeHCO 3 → MeCO 3 + CO 2 + H 2 O

B) Carbonates are converted to bicarbonates with an excess of carbon dioxide and water. This reaction is the cause of the destruction of buildings built of limestone, under the action environment: from rain and carbon dioxide contained in the air, insoluble carbonates are converted into soluble hydrocarbons.

MeCO 3 + CO 2 + H 2 O → MeHCO 3 , when heated - on the contrary, bicarbonates turn into carbonates

We used to observe chemical reactions in the school laboratory, in test tubes. But the same processes occur in nature, around us. He will tell us about this now ... (student's message about the formation of karst caves)

Student's report on the formation of stalactites and stalagmites.

There may be large deposits of limestone in the earth's crust. Under the action of water and carbon dioxide, insoluble carbonates are converted into soluble hydrocarbons, which are washed out with water. As a result, voids (karsts) are formed in the earth's crust. These voids are called karst caves. Marble Cave is one of the most beautiful caves in Crimea, which is located seven kilometers from Alushta on one of the Chatyrdag plateau at an altitude of 1000 meters above sea level.marble cavecreated over hundreds of thousands of years and formed from marbled limestone. This is a real underground natural museum, where you can see amazingly beautiful stone waterfalls, cascades of small lakes, sintered curtains, placers of cave pearls. By the richness of the stalagmite and stalactite decoration, as well as the amenities and services for tourists, it is one of the five most famous caves in Europe. Where did this miracle of nature come from? All this is created from calcium compounds, or rather from calcium carbonate and calcium bicarbonate. The formation of stalactites and stalagmites in caves can be explained as follows. Rainwater, seeping through the roof of a limestone cave, dissolves the limestone contained in the rock. Of course, the water does not flow down from the arch of the cave in a stream, but drips very slowly, so slowly that part of it has time to evaporate, and the limestone dissolved in it again crystallizes in the form of stone “icicles” hanging from the ceiling. This is how stalactites are formed.
Drops of lime water that have fallen down also evaporate, and the limestone dissolved in them remains at the place where the drops fall, forming vertical cone-shaped growths - stalagmites.

The longest is Mammoth Cave in Kentucky, USA. The total length of underground corridors is almost 600 km. The Krubera-Voronya cave is currently the deepest cave in the world (more than 2000 m deep), it is located in the Arabica mountain range in Abkhazia.

The formation of karst in areas of residential or industrial buildings can lead to the fact that residential buildings, industrial buildings, and other buildings fall underground.

When a cold solution of calcium bicarbonate with a current of water is on the surface of the earth, it heats up under the sun's rays and decomposes into calcium carbonate, carbon dioxide and water. Thus, calcium carbonate is again precipitated, only in a different place.

Teacher : Did you know that 3% baking soda solution or sodium bicarbonate tablets can be used to relieve heartburn in the stomach? To explain what the use of these substances is based on, let's do the following experiment:

(performing a laboratory experiment according to the instructions):

1. In a test tube with 2-3 ml of Na solutions 2 CO 3 (1 option) and NaHCO 3 (2 option)

add a drop of litmus.

2.What are you watching?

3. Explain the color of litmus in solution.

4. Think about why sodium bicarbonate is used to eliminate heartburn? (hint: remember what environment is in the stomach).

Teacher: salts of carbonic acid, carbonates and bicarbonates in water undergo hydrolysis, have an alkaline reaction of the environment, therefore they can be used to neutralize the acidic environment.

On your tables are samples of chalk, marble, limestone. Here you can also see shells, skeletons of starfish, corals.(appendix 1, slide)

What do these rocks and minerals and wildlife have in common? To answer these questions, I suggest you perform a laboratory experiment:

1. To samples of chalk, marble, limestone (1 option); shells, starfish and corals (option 2), add HCl drop by drop.

2. What are you observing?

3. What do you think, what substance is included in their composition?

(students make a guess: carbonates)

Teacher: Indeed, the main component of these objects of animate and inanimate nature is calcium carbonate. It is no coincidence that N.M. Fedorovsky wrote in his poem about minerals:

According to the formula, no matter how you look,

They do not differ in any way:

All the same calcium tse o three,

Both marble and limestone. (appendix 1, slide)

Teacher . Have you ever thought about why, wanting to evaluate some work of art, they say: "This is a pearl ...". And then they call it an art form. But why a gem? But because pearls have always been considered a symbol of the highest manifestation of beauty. So what are pearls? (pearl message)

Student message about pearls

Pearls are hard rounded formations extracted from the shells of some molluscs. Valued as a precious stone and used to manufacture jewelry. Many peoples of the East (and even the West) have an infinite number of legends explaining the origin of pearls from tears of happiness or grief, tears of goddesses, tears of beautiful or ugly women, from morning dew, and so on, but none of them points to the true creator of this marvelous treasure - a nondescript slug, a mollusk ... Pearl is not a "stone". Pearls are a waste product of a mollusk. A pearl is formed inside the shell of a mollusk as a result of a foreign object (grains of sand, etc.) getting there. Around the “seed” object, mother-of-pearl is deposited, forming concentric layers with thin films. Mother of pearl is an organomineral aggregate of calcium carbonate (most often in the form of aragonite) and conchiolin (horny substance). Pearls usually have White color, sometimes cream or pink; there are also yellow, green, black and even blue pearls. Blue pearls are very rare, highly valued and attractive due to their rare, blue, lead gray hue.
Pearls have always been a favorite jewelry among many peoples, they were honored for their delicate beauty and original shape.

Unfortunately, not a single ancient pearl has survived to our time due to its short age.

This is due to the fact that over time organic matter, which is in them, dries up, undergoes decomposition. History knows many examples of large pearls. However, none of them has survived to this day: pearls do not last more than 150-200 years (the exception is cases when there is no air access; during excavations, pearls were found in layers 2000 years old). The oldest pearl whose history can be traced is the Peregrine, owned by Elizabeth Taylor.

Peregrine is a rather large pear-shaped pearl of 50.95 carats (10.19 grams). It has a bright milky color. Peregrina, which means “traveler” or “pilgrim” in Spanish, has indeed come a long way before being included in the collection of a Hollywood actress. The first mention of Peregrine dates back to the 16th century - the pearl was a wedding gift from the Spanish king Philip II to his second wife, Queen of England Mary I the Bloody. In several portraits, Mary is depicted with this pearl.

I think you have already understood that carbonic acid salts are widely distributed in nature and are involved in many processes. Now I invite you to work with the texts and learn about the meaning and application of carbonates and bicarbonates in everyday life.

Text for group 1

Carbonates in the form of limestone are used in construction. When limestone is burned, calcium oxide, or quicklime, is formed:

CaC0 3 \u003d CaO + C0 2.

When water is added to calcium oxide, slaked lime is formed:

CaO + H 2 0 \u003d Ca (OH) 2.

Hydrated lime is used in construction for whitewashing, plastering, while sand is added for strength. Calcium hydroxide, reacting with atmospheric carbon dioxide, turns into calcium carbonate and gradually hardens.

Many monuments of sculpture and architecture are made of limestone and marble. You probably know that over the past decades they have begun to deteriorate more than in all the previous time. This happens under the influence of acid rain. Acids are produced by the interaction in the atmosphere of nitrogen and sulfur oxides formed during combustion various kinds fuel, with water. Under the influence of these acids, carbonates are washed out of cultural monuments:

CaC0 3 + H 2 S0 4 = CaS0 4 + C0 2 + H 2 0.

AT recent times to protect them, coatings of high-molecular compounds - silicones are used.

Text for group 2

Water in nature is soft and hard. Rigid called water containing various salts. Distinguish between temporary and permanent hardness.

Temporary stiffnessdue to the presence of soluble calcium and magnesium bicarbonates - Ca(HC0 3 ) 2 and Mg(HC0 3 ) 2 . These salts are destroyed by boiling, so this hardness is called temporary.

Permanent hardnessdue to the presence of other salts, such as sulfates (CaS0 4 ) and chlorides (CaCl 2 ).

The use of water with increased hardness in everyday life leads to additional material and energy costs. For example, when boiling such water, a thick layer of scale is gradually formed on the walls of the dishes, formed by insoluble calcium and magnesium carbonates:

Ca (HC0 3) 2 \u003d CaC0 3 + H 2 0 + C0 2.

The thicker the scale layer, the longer the kettle boils.

When washing in hard water, more detergents, in particular soap, are consumed. In this case, part of the soap is spent on the binding of calcium and magnesium ions, as a result of which insoluble calcium and magnesium compounds are formed, which precipitate.

Currently, synthetic detergents are used for washing, the effectiveness of which depends little on the hardness of the water. However, synthetic detergents are slowly destroyed in the natural environment and cause pollution of water bodies.

Water can be softened chemically. To do this, sodium soda is added to hard water. 2 C0 3 or lime water Ca(OH) 2 while calcium carbonate precipitates. Temporary hardness is also eliminated by boiling.

How does hard water affect the human body? Although calcium and magnesium ions play an important role in the body's water-salt balance, their excess can lead to metabolic disorders and the development of diseases, such as kidney stones.

Our great-grandmothers tried to wash their faces, wash their hair with melt or rain water, which contains a very small amount of salts. Such water does not dry the skin, and the hair after washing is soft and shiny. Please note that softened water is present in the composition of creams, and shampoos, bath foams necessarily contain water softeners.

Vegetables and meat cooked in soft water are much tastier and juicier. Hard water is not recommended for cooking, as it reduces the taste of dishes.

Text for group 3.

Carbonates are used in the manufacture of glass. The raw materials for obtaining ordinary glass are pure quartz sand, soda and limestone. These substances are thoroughly mixed and subjected to strong heating (up to 1500 ° C). The following reactions take place:

Na 2 C0 3 + Si0 2 \u003d Na 2 Si0 3 + C0 2;

CaC0 3 + Si0 2 = CaSi0 3 + C0 2 .

Molten glass cools gradually and can be molded into various shapes.

Limestone and clay containing silicon oxide are the main raw materials for the production of cement. These substances are thoroughly mixed and the mixture is fired in inclined cylindrical kilns, which are up to 200 m long and about 5 m in diameter. During the firing process, the kiln slowly rotates, the raw materials gradually move, and complex reactions occur between clay and limestone. The resulting substances are sintered into pieces, after cooling they are ground to a fine powder. Cement is widely used in construction as a binding material.

Ammonium and sodium bicarbonates are used in confectionery, they easily decompose when heated, forming gases that loosen the dough and make it fluffy.:

NH 4 HC0 3 \u003d NH 3 + H 2 0 + C0 2; 2NaHC0 3 \u003d Na 2 C0 3 + H 2 0 + C0 2.

Sodium carbonate, or soda, is used in fire extinguishers. The fire extinguisher is a steel cylinder filled with a solution of soda. An ampoule with sulfuric acid is placed on top. When the fire extinguisher is activated, the ampoule breaks, sulphuric acid reacts with sodium carbonate, carbon dioxide begins to be released and foam is formed. Foam stops the access of oxygen to the burning object, and thus the fire is extinguished.

Text for group 4

In our country, significant areas are occupied by acidic soils. Presence in acidic soils a large number hydrogen ions sharply degrades the fertility of the earth. To neutralize acidity and increase fertility, liming of acidic soils is carried out, i.e. limestone CaCO2 is added to the soil 3 and dolomite CaCO 3 MgC0 3 in shredded form.

Liming has been known to man for a long time. The farmers of Gaul and the British Isles used limestone and chalk in fields, meadows and pastures about 2000 years ago.

The mineral malachite (CuOH) also belongs to carbonates. 2 C0 3 . It is used as a decorative and ornamental stone. The beauty of malachite is given by a bright green color, an intricate pattern, often creating a mysterious picture. In the Winter Palace, located in St. Petersburg, there is a malachite hall. Malachite also produces green dye.

After working with the texts, fill out the table in r.t.s 185 No. 5

Let's summarize. Carbonic acid and its salts largely shape the appearance of the planet. They are widely used in economic activity person. Of particular importance is CaCO 3 . It is to him that we owe the architectural appearance of our cities. But in order for carbonates to work for a person, knowledge of scientific laws, chemical processes occurring around us is required.

D.z with. 244 - 247

Reflection: compiling a syncwine

1. Noun
2. 2 adjectives
3. 3 verbs
4. Sentence
5. Word

Now think about everything that happened in the lesson.

1 I learned a lot

2. I will need this in my life

3. There was something to think about in the lesson

4. I received answers to all questions

5. I worked hard in class

2. Meanwhile, the Needlewoman returns, strains the water, pours it into jugs, and what an entertainer: if the water is unclean, she folds a sheet of paper, puts coals in it and pours coarse sand, inserts that paper into a jug and pours water into it, and water something, you know, it passes through the sand and through the coals and drips clean, like crystal, into a jug. Russian folk tale "Moroz Ivanovich"

2. What cleaning methods does Needlewoman use? B) filtration A) distillation O) adsorption M) crystallization

3. Carbon monoxide! cried Holmes. “Wait a little. Now he will leave. Looking through the door, we saw that the room was lit only by a dim blue flame, flickering in a small copper brazier in the middle ... A terrible poisonous fumes were drawn into the open door, from which we choked and coughed. A.K. Doyle "The Case of the Translator"

3. Find the chemical errors in the read passage. Why couldn't Holmes and his companions determine the presence of carbon monoxide in the room by the signs described? N) carbon monoxide is odorless D) carbon monoxide has a pleasant smell A) when carbon monoxide poisoning, a person does not cough

4. In the Arabian desert grows a tree Caratina silikva (caratina silikva), the fruit seeds of which always have the same weight in any year and on any tree. Therefore, the jewelers of antiquity used such weights for their scales, calling them carats. Nowadays, there is a carat test of gold and precious stones.

4. What is the weight of one carat? I) 100 g H) 0.5 g S) 0.2 g R) 0.1 g

5 . - Have you heard about the "dog cave" effect in Italy? There is a cave there. The person will enter and walk around, and the dog or rabbit will die in a few minutes. - Why? - Carbon dioxide is released from a volcanic crack ... V. Korotkevich "Black Castle Olshansky"

5. Why does a person remain alive in the “dog cave”, while dogs and other small animals die? S) CO 2 is heavier than air and accumulates at the bottom A) CO 2 is safe for humans, but harmful to animals G) a person enters a cave in a gas mask.

Carbonic acid H 2 CO 3 Salts of carbonic acid Medium salts - carbonates MeCO 3 Acid salts - bicarbonates MeHCO 3 Salts of carbonic acid Medium salts - carbonates MeCO 3 Acid salts - bicarbonates MeHCO 3

The value of salts of carbonic acid Ornamental stone in sculpture For liming soils with their excessive acidity. Construction Materials(chalk, marble, limestone) Calcium carbonate CaCO3 (chalk, marble, limestone)

Parthenon (5th century BC Athens) Nike of Samothrace (11th century BC Louvre Paris) CARBONATES IN SCULPTURE AND ARCHITECTURE

The value of carbonic acid salts Soda ash Na 2 CO 3 and crystalline soda Na 2 CO 3 10 H 2 O Soap production, in everyday life as detergent. Glass production. Paper production

Importance of salts of carbonic acid In the production of fire extinguishers In medicine for the manufacture of medicines In cooking for loosening dough Drinking (food) water NaHCO 3

General chemical properties 1. Decomposition on heating MeCO 3 → MeO + C О 2 (excluding group I A metal carbonates) MeHCO 3 → Me С O 3 + CO 2 + H 2 O 2 . All salts interact with acids - they give a qualitative reaction to CO 3 2 - and HCO 3 ions - MeCO 3 + H n KO → MeKO + CO 2 + H 2 O MeHCO 3 + H n KO → MeKO + CO 2 + H 2 O 3 . Salts of carbonic acid enter into exchange reactions with other salts if insoluble or poorly soluble substances are formed. 4. Carbonates are converted into bicarbonates with an excess of carbon dioxide and water. MeCO 3 + CO 2 + H 2 O → MeHC O 3 Hydrocarbons cause temporary water hardness.

Ways to eliminate temporary water hardness 1. Boiling When boiling, soluble calcium and magnesium bicarbonates are converted into insoluble carbonates. 2. Addition of soda (Na 2 CO 3) Eliminates not only temporary, but also permanent hardness of water created by chlorides and sulfates of calcium and magnesium.

Establish a correspondence between the left and right parts of the equations the left parts of the equations heating 1) 2KHCO 3 \u003d heating 2) CaCO 3 \u003d 3) Na 2 CO 3 + 2HCI \u003d 4) C aCO 3 + CO 2 + H 2 O \u003d 5) 2KHCO 3 + H 2 SO 4 = right hand sides of the equations a) K 2 SO 4 + 2CO 2 + 2H 2 O b) Ca (HC O 3) 2 c) K 2 CO 3 + CO 2 + H 2 O d) CaO + CO 2 e ) 2NaCI + CO 2 + H 2 O

answers 1 - c 2 - d 3 - e 4 - b 5 - a